IntelliMouse Trackball is designed to leverage the success of the IntelliMouse by incorporating the wheel technology in a trackball format. Utilizing the finger instead of the thumb to manipulate the trackball, the IntelliMouse TrackBall is ergonomically designed for greater user comfort. The trackball format allows users to conserve desktop space by allowing the user's hand to remain in a stationary position. It's the smart, comfortable way to work!